Hiyori Kazane

Hiyori Kazane is a second-year student at Tomoki's school. In reality, Hiyori is an Angeloid who was first seen inside some sort of sleeping chamber, which allows them to dream, when Sugata went to Synapse. The chamber connects her to her body on Earth, which functions like an avatar. She has feelings for Tomoki and joins the New World Discovery Club in order to get closer to him.

Hiyori Kazane
When the shy and timid second-year student Hiyori Kazane first walked into The New World Discovery Club to ask permission from club leader, Eishiro Sugata, to join their club, it came as a shock to Tomoki Sakurai and all within the small club at Sorami High School. She was the first person other than those involved with their group that sought to join their club, and to Tomoki, this meant something suspicious was up. Not sure what to think of the sudden request, Eishiro is reluctant at first to accept her into the club, but since her joining their club will result in a larger budget from the school, he gladly accepts her into the New World Discovery Club. Hiyori Kazane is a mostly quiet, shy girl who joined the club in the hopes of getting closer to Tomoki (whom she has strong feelings for, even though they have never been together before). Her kind behavior towards Tomoki (even when he acts extremely perverted around her) and disregard for his wild and twisted antics causes some emotional discomfort for not only Sohara Mitsuki (who secretly loves Tomoki), but for Angeloids Nymph and Astraea as well, for they too harbor strong feelings for Tomoki and do not appreciate this new girl getting involved.

Unknown to Tomoki, Sohara, and Mikako Satsukitane, Hiyori is not the simple 2nd-year student who she appears to be. In fact, she is hiding a major secret that if found out by others, would result in a complicated and potentially dangerous situation that could result in her death. In one of his earlier trips to the mysterious world of Synapse (using one of Nymph's machines to be transported there), Eishiro Sugata ventured into a massive domed complex located on one of the many floating islands in Synapse to explore the world of the angels in depth. After searching around, he came across a gigantic room filled with thousands of metal capsules that each contained the bodies of slumbering angels, each living out a "dream" on Earth as a way of keeping occupied in Synapse. While he was searching the room, he came across a capsule that contained a familiar figure, and to his horror and amazement, inside was a winged version of second year student Hiyori Kazane, sleeping peacefully within her capsule as she muttered something related to Tomoki. Only Eishiro (along with all three of the Angeloids back on Earth) knows the truth behind Hiyori's past and who/what she really is.

Tomoki, in shock that someone would be insane enough to actually join their club (which gets involved in wild, crazed misadventures on a regular basis), decides that action must be taken to prevent her from being with the club. Over the next few days, he tried everything that he could think up (a series of bizarre, perverted "purity" tests that he thought would prevent her from staying involved with the club) to scare her away to the point that she would never come back, but she completes all of his tests and did not leave the club (much to Tomoki's bewilderment). He begins to harbor feelings for Hiyori, who seems to always ignores his faults and treats him so kindly compared to Sohara and the Angeloids whenever he acts perverted in front of them.

Hiyori's Awakening

He is flabbergasted and in complete disbelief when she comes forth and confesses her strong feelings of love for him (no one, especially a girl, has ever taken such a interest in him before, and this rocks Tomoki to the core). He begins to fall in love with Hiyori, and dreams of the things that they can do together in the future, but when he goes to confess his feelings for her, a major tragedy occurs. In a matter of seconds, she is brutally hit and killed upon impact by a slumbering truck driver who is traveling at a high rate of speed right in front of him. To his horror, she begins to dissolve away before his own eyes, and his memories of her existence begin to evaporate away (along with Sohara, Eishiro, and Mikako, who lose all memory of her existence after she dies).

Eishiro, who is currently making another trip to Synapse to learn more about the inhabitants who call it home, suddenly begins to forget everything he knew about Hiyori as she dies back on Earth. With only several minutes before every memory of her disappears forever, he charges past the twin Harpies (who are searching for him since he is trespassing there) and back into the dome, hoping to see her awake from her "dream" on Earth. To his amazement, Hiyori sits up from her sleep, a look of shock and horror on her face as she realizes that she has awakened from the dream and can never experience the same dream again. They lock eyes and seeing Eishiro before her brings tears to Hiyori, who knows that soon no one that she met back on Earth will ever remember her existence. She goes into a panic, and tries to re-dial the same dream, but is interrupted by the arrival of the mysterious Man of Synapse (along with the Harpies, his two Angeloid servants). He reminds her that she can never have the same exact dream again, and decides to let Eishiro go (since he has been entertained and Eishirou will soon forget everything in several moments).

Angeloid Hiyori

Hiyori makes her return later in the story as a newly converted 2nd Generation Angeloid who is sent by her current master (who is The Man of Synapse) to eliminate Tomoki Sakurai, his fellow human friends, and wipe out Ikaros, Nymph, and Astraea. She was converted into a 2nd Gen. Angeloid (Type Zeta) by the Man of Synapse, who promised her that she could "continue" to live her life out on Earth. Wielding the powerful staff known as the "Demeter" (which grants her total control of the elements and weather around her), she creates a mighty vortex of wind that drops the air pressure down in the city of Sorami to dangerously low levels (to the point where Tomoki suffers crippling pain and begins to bleed from his ears as a result) in order to complete her primary objective. She is met by the three very enraged Angeloids (upset that Synapse would launch such an attack upon the poor inhabitants of Sorami) and engages them in combat.

It is only after Nymph uses her mastery of hacking abilities into Hiyori's system to override her system that frees Hiyori from the iron-fisted rule of The Man of Synapse and allows for her to return to Earth so that she can begin again. Tomoki is surprised when he finds out of her return and decides to become friends with her once again. But Hiyori decides shortly afterwords to resign from The New World Discovery Club and sets off to enjoy her new freedom on Earth as a free Angeloid, taking leave from being involved with their daily lives. She makes a rare appearance in later chapters of the manga, most notably when she discovers the traumatized and injured form of Chaos that is laying on the dirt road and is crying next to her vegetable garden after taking massive damage when attempting to return back to Synapse (which her former master, the Man of Synapse, forbids and launches a massive shot of pure energy via the powerful Zeus Canon at her, damaging one of her wings in the process). Hiyori is last seen watching in complete shock as Chaos launches up into the air and rushes off into the distance, making a beeline towards where Tomoki's house is. In the chapters that follow, Hiyori is seen from time to time, usually shown tending to her vegetable patch or doing minor chores.

Ikaros Melan Arc
Hiyori Kazane appears towards the end of the Ikaros Melan Arc, seen standing alongside Sohara and the others as Ikaros, Nymph, and Astraea struggle with the newest threat sent down from Synapse. Although she does not directly contribute towards the fight, she has come to Tomoki's house in her Angeloid gear in case that she is needed in the struggle against Ikaros Melan and the advanced Angeloids that the Man of Synapse has sent to kill Tomoki. In the aftermath of Ikaros Melan's defeat and the snapping of the Man of Synapse's sanity, Hiyori joins the others at the hospital to wish the battered Tomoki well as he tries to recover from his terrible injuries that he sustained at the hands of Ikaros Melan.

Personality
Hiyori is a shy person, she loves to grow crops, and is kind. Though, whenever Tomoki walks by when she's farming, she hides because she's embarrassed when Tomoki sees her dirty.

But in Hiyori's Angeloid form, Zeta, is still the same. In the movie, Zeta is controlled by Man of Synapse, which she tries to destroy Tomoki's town, himself, and his friends. (including Ikaros, Nymph, and Astrea) When being controlled, she is silent and only uses her abilities to kill his fellow friends and him too. After putting on Hiyori's bell ornament she had dropped, Tomoki returns it to Zeta, and puts it back on resulting that she remembers him. The "tick tock" of a clock ticks, which she warns Tomoki that she will explode, so in return, she had kissed Tomoki and thanked everyone. Sadly, she had exploded, leaving only her feathers behind.

Appearance
Her first appearance was in the 5th episode of the second season of the anime, where she has a very limited role. She is not actually introduced in the anime at that time but it is foreshadowed that she will be a significant and important character in the future. Hiyori makes an appearance movie Sora no Otoshimono the Movie: The Angeloid of Clockwork, she comes in as human, but she then decreases in the movie because since she was controlled by the Man of Synapse, a bomb was attached to her, and then she had exploded in mid air resulting her death.

In manga, some of the things that happened in the movie are also transferred in the manga. She stays Zeta forever since she had lost her biological body. Around chapter 36-40, she has made her appearance. The thing is, it's different from the movie. She doesn't die in the manga version, she just flies away and kisses Tomoki. But, the next day, she returns to school, but in her Zeta form.

Abilities and Weapons
After being fully converted into an 2nd Generation Angeloid after the Minos gets his hands upon her to use against Tomoki and the other Angeloids down on Earth, Hiyori gains the powers of flight, speed, and the abilities to control and bend the elements around her to her will, made possible with the aid of her powerful Demeter staff. She uses these powers in order to carry out a failed attempt at killing Tomoki Sakurai by lowering the air pressure around Sorami to a dangerously low level, effectively putting the entire town at a high risk of death. As she lowered the pressure around them, Tomoki begins bleeding from his ears. In the anime, Hiyori was the power over time and possibly space.

Relationships

 * Tomoki Sakurai - Friend and love interest.


 * Sohara Mitsuki - Friend and love rival.


 * Eishirou Sugata - Friend.


 * Mikako Satsukitane - Friend.


 * Nymph - "Sister" and love rival.


 * Ikaros - "Sister" and love rival.


 * Master of Synapse - Former master and enemy.


 * Daedalus - "Mother" and Creator.


 * Chaos -  "Sister" and Friend.


 * Astraea - "Sister" and love rival.


 * Oregano - "Sister" and Friend.

Trivia

 * Her name sounds like Shiori Kazami, the name of Shun Kazami's mother (from Bakugan Battle Brawlers).
 * Her weapon "Demeter" is named after the Greek goddess of agriculture and crops.
 * Deceased as of manga chapter 70. Chaos at first sought to eat her against Hiyori's will, but after Hiyori beheld a "flow of memories" from Chaos, showing the level of moral damage inflicted by Chaos's creator Minos, Hiyori realized that Chaos needed someone to set her moral compass straight. She then willingly impaled herself onto Chaos's wingtip, giving Chaos all her powers and knowledge, including a strong sense of right and wrong.
 * Forte 4: 9:33 - 10:41
 * Hiyori was narrating in the first movie.
 * In the new 2014 movie Sora no Otoshimono: Eternal my master, Hiyori will be one of the supporting charaters
 * In the first movie Hiyori has black hair, but in the second movie trailer she is shown having navy blue hair like the manga.
 * In the first movie Hiyori met Tomoki when they were just children on their favorite place.